in JS backend, importcpp string is used to get a function pointer by the compiler cause a syntax error with # in generated output

[mildred]

I got a strange javascript error with my code: SyntaxError: private fields are not currently supported

The generated javascript function looks like:

function bind_value_12246249() {
    function HEX3Aanonymous_12246256(re_12246262) {
        function HEX3Aanonymous_12246263(e_12246265) {
          // ...
        }

      var F={procname:"bindValue.:anonymous",prev:framePtr,filename:"util.nim",line:0};
      framePtr = F;
        if (re_12246262.init) {
        F.line = 237;
        re_12246262.node.addEventListener("change", HEX3Aanonymous_12246263, false);
        }

        F.line = 239;
        (re_12246262.node).value = #.value;
      framePtr = F.prev;

    }
    // ...
}

The error is: (re_12246262.node).value = #.value; which is obviously not a valid javascript syntax (or perhaps will be with private fields, but I suppose this was not intended). The nim procedure is:

proc bindValue*[T](typ: typedesc[T]): ProcRefresh[T] =
  return proc(re: RefreshEvent[T]) =
    if re.init:
      re.node.addEventListener("change") do(e: dom.Event):
        re.set(re.node.toJs["value"].to(T))
    re.node.toJs.value = value

There is an error in the above function, on its last line (re.node.toJs.value = value), the value on the right hand side is not bound to a function argument. I believe it's not bound in the global scope too (but perhaps I'm wrong here). In any case, it should not produce erroneous javascript.

The correct writing of that line is: re.node.toJs.value = re.data.toJs

I believe the compiler should have stopped producing an error telling that value cannot be bound to anything.

The error can be reproduced with: https://github.com/mildred/nclearseam/commit/5706b88750033dd13f2f0cd1f9cb1f2e40fce009

$ nim js samples/compute/calcul_meubles
$ python -m http.server 8000
$ firefox http://localhost:8000/samples/compute/

Nim version:

Nim Compiler Version 1.2.0 [Linux: amd64]
Compiled at 2020-04-03
Copyright (c) 2006-2020 by Andreas Rumpf

active boot switches: -d:release

[mildred]

I was wrong with value not bound in scope, there is in scope the dom module with:

proc value*(n: Node): cstring {.importcpp: "#.value", nodecl.}
proc `value=`*(n: Node; v: cstring) {.importcpp: "#.value = #", nodecl.}

It seems the first procedure has been used but without any argument, and the # has been preserved in the javascript output.